Pouch or packaging for foodstuffs made of a peelable film and process for the production thereof

ABSTRACT

An airtight pouch or packaging ( 10, 20 ) made of synthetic material for the preservation of food products ( 12 ) is obtained by sealing ( 13, 14, 15 ) and cutting said synthetic material by an automatic packaging machine with a horizontal or vertical motioning of the product. The packaging ( 10, 20 ) is constituted by a single peelable type film ( 11 ) consisting of an oriented polyamide layer coupled with a coextruded peelable polyethylene layer, said film being folded once on the polyethylene layer side in order to form the inner part of said packaging.

FIELD OF THE INVENTION

[0001] The present invention relates to a peelable film pouch orpackaging to be used for storage of food products at large,advantageously cheese, said pouch or packaging having such aconformation that once opened, it can be closed more than once for thepreservation of freshness and flavour of the food therein contained.

[0002] Furthermore, the present invention relates to a process for theproduction of a peelable film pouch or packaging of the type mentionedabove.

[0003] Yet, the present invention relates to a machine suitable forcarrying out said process.

[0004] The present invention finds a particularly suitable employment inthe field of food industry and in that of food packaging.

STATE OF THE ART

[0005] Packagings for storage of foodstuffs in general are known in theart, said packagings being made of a suitable plastic film and obtainedby sealing, according to well-known techniques in the field.

[0006] Examples of such packagings may be found in documentsEP-A-696991, EP-A-516393, EP-A-608123.

[0007] A typical packaging process is accomplished by an automaticmachine called “flow-pack”, wherein, once placed in a horizontalposition, a certain produce is made to move forward along a suitableconveyor whilst a plastic film is unwrapped from a suitable supportspool and suitably shaped in such a way to wrap the produce itself.

[0008] In the “flow-pack” machine, a suitable bag forming means ispresent, and this is generally made of a tubular plate, which issuitable for folding the packaging plastic film so as to allow thepacked product to be introduced into said tubular plate and wrapped inthe plastic film after that.

[0009] During the advancement of the product within the forming tube,the plastic film is initially made to undergo a first sealing operationwhich is longitudinal with respect to the forward direction followed bythe product itself.

[0010] Said first sealing operation is generally carried out by using aplurality of coupled rollers which are positioned opposite to each otherand on both sides of the product so as to act on both sides of theplastic packaging film.

[0011] In particular, said rollers normally comprise a first couple ofrollers that accomplish their function of leading the sliding of thefilm, a second couple of rollers that carry out the longitudinal sealingoperation of the film, along the advancement direction of the product, athird couple of rollers equipped with a cutting blade in order toeliminate the portions of film that are found beyond the sealed edges,and a fourth couple of rollers generally made of rubber for dragging thefilm itself.

[0012] According to other forms of embodiment, said first sealingoperation can be carried out by means different from those describedabove, that is by sealing blocks.

[0013] Once the first longitudinal sealing operation has beenterminated, a second sealing is carried out transversally with respectto the forward motion of the product, so as to obtain a first short sideof a given packaging; this second sealing is carried out by means of acouple of sealing plates which are placed downstream from said rollers.

[0014] In case of an advancement of the product on a continuous basis,said sealing plates are fixed onto a moving mechanism that goes forwardin parallel with the product in such a way that the plates remain incontact with the film to be sealed for a predetermined length of time;in case the product advances intermittently, the sealing plates areuniquely capable of a back and forth movement towards each other.

[0015] Once said second sealing operation has been terminated, theplates are opened and, in case of intermittent advancement of theproduct, this is made to move forward stepwise, so that said sealingplates can be closed again downstream from the product in order to becapable of carrying out a third sealing operation which is transversalto the forward motion, in so doing obtaining the short side of thepackaging.

[0016] In case of a continuous advancement of the product, the mechanismon which the sealing plates are fixed causes their withdrawal and theirclosing exactly in correspondence with the second side to seal.

[0017] During the third sealing operation the plastic film cuttingoperation is carried out and so the product results to have beenadequately packed and and it is ready for the following packaging andstorage phases.

[0018] The above mentioned operations are suitable for a productmotioned in a horizontal direction, whereby the product is placed andmade to advance headways on the conveyor which is suitable for making itmove forward.

[0019] The packing of a certain horizontally positioned product on anadvancement conveyor shows a considerable disadvantage due to thepositioning of the longitudinal side of the packaging achieved by thefirst sealing operation, on the flat surface of the product and at theback of the packaging.

[0020] In such a way there does not result to be allowed the reading ofwhat printed on the back of the packaging which is relative to theproduct therein contained, its ingredients, its origin, and so on;information to which customers are particularly attentive and sensitive,but which result to be hard to be accessed to because of the folded andsealed side.

[0021] In case of a packaging of the horizontal type, the motioning ofthe product lying on one of its small sides, that is moving sideways,would be an adequate solution to solve that problem, since thelongitudinal sealing line could be placed along one of said small sidesof the product, but a device suitable for unwrapping the film and forcarrying out its sealing and cutting between one unit of product and theother would require additional devices which were made of several pieceswhose constructive features were excessively complicated and whoseproduction costs were too high in order to be paid in a convenient wayfor the producer.

[0022] Attention is drawn to the potential encumbrance and to theensuing constructive difficulty associated to it, of a device that issuitable for carrying out a transversal sealing that must motion asealing plate of a remarkable size along a route that is basically ovalor elliptically shaped in order for the product to be followed as longas it advances on the conveyor during the sealing of the front limbs andafterwards and for the sealing plate to move back to the startingposition to carry out a further sealing of the upper edges.

[0023] Such a solution which is easily viable for products that areplaced with the flat on the conveyor itself, is found to be remarkablydifficult in case the products were positioned so as to lie on one oftheir small faces.

[0024] It is further known in the praxis to carry out the abovementioned packing steps in a modified atmosphere, in order to controlthe chemical, enzymatic or microbiological reactions that take place onthe product, and completely minimise or eliminate the main causes ofdegradation of the product itself.

[0025] A controlled atmosphere is generally obtained employing a gas ora mixture of gases among which there are nitrogen, carbon dioxide, andoxygen, said gases being used as they hinder the oxidation phenomenainvolving pigments, flavours and fats of the product, as well as todelay the growth and reduce the proliferation rate of molds and aerobicbacteria.

[0026] The gas or the mixture of gases employed are suitably blown induring the packaging process, down an injection tube positioneddownstream from the first longitudinal sealing operation and immediatelyupstream from the sealing plates that accomplish the transversalsealing, to obtain a perfectly airtight packaging.

[0027] In the state of the art there are also found to be knownpackagings of the above described type which are equipped with are-closable zip closing system which is either placed below or abovesaid longitudinal type sealing (see for example U.S. Pat. No. 4,589,145,EP-A-513550, U.S. Pat. No. 4,240,241, U.S. Pat. No. 4,969,309, U.S. Pat.No. 4,617,683.

[0028] A first important drawback of certain solutions known in the artis constituted by the packaging being formed by coupling two plasticfilms which are simultaneously unwrapped from two separate reels.

[0029] This kind of solution is bulky and requires a great accuracywhile unwrapping the films, since these can be provided with wordings ordesigns which need to be matching in respect of each other when the bagor packaging is wrapped around the product.

[0030] The type of packaging having a zipper placed inside of the sealedarea presents more than few disadvantages because the positioning of thelock below the longitudinal sealing does not guarantee a perfectairtightness of the packaging just as on the other hand it results to benecessary in order to preserve the food product therein contained.

[0031] On the other side, the known packagings provided with a zipperplaced outside of the sealing line involve other disadvantages anddrawbacks which are essentially due to the fact that when the film isfolded in order to form the pouch, the welding operation is carried outbetween respective inner and outer portions of the film; by way ofexample, in a pouch made of multi-layer peelable film constituted by aninner polyethylene layer and an outer polypropylene layer, when theinner and outer layers are welded to each other the resulting chemicallink is often not very homogeneous and the airtightness of the innerpart of the pouch cannot be guaranteed.

[0032] It is indeed easy to understand that the sealing of the zipperonto the plastic film does not indeed give the full certainty that thepackaging is kept in a perfectly airtight condition, mostly in the areascovering the extreme edges of the zip itself.

[0033] Furthermore on account of its inherent features, the zip cannotbe considered to be an airtight closing means.

[0034] This means that types of packaging equipped with the abovedescribed zip cannot be used as airtight packagings in a modifiedatmosphere.

[0035] The plastic films used for the accomplishment of the packagingsof the prior art are generally chosen in the group comprising:polyethylene, polypropylene, polystyrene, polyvinylchloride,polyvinylidene chloride, polyesters, polyamides.

[0036] More particularly, the plastic films resorted to are laminatescoupled to form a multilayer structure of the polypropilene/polyethyleneor polyester/polyethylene, or further of the polyamide/polyethylenetypes.

[0037] The main disadvantage of the totality of the packagings of theprior art so far described is the impossibility they have to be sealedagain after being opened once.

[0038] This means that once a typical packaging of the prior art such asone used for cheese or meats has been opened, it is not capable ofguaranteeing an adequate preservation of the product that has not beenconsumed and which is left therein.

[0039] Furthermore, at the present moment most of the times, when such apackaging is opened, this ends up being torn and almost entirelydestroyed because the consumer finds it impossible to follow the giventearing lines in order to be able to open it and proceed to theextraction of its content.

[0040] The sealing material used, which is normally constituted bypolyethylene, does not indeed allow the sealing to be delaminated andthe consumer cannot therefore avail of the sealing lines such as thosewhich are to be followed during the opening of the packaging itself.

[0041] Therefore if it is placed back into its original packaging, theproduct which has not been consumed is unavoidably in contact with theoutside environment, provided that the packaging is still in such acondition to be used, i.e. if it has not been completely destroyed atthat stage.

[0042] It ensues from this that there is a loss of freshness and taste,because the general hygienic level of the product at the time ofpurchase when the packaging was perfectly sealed has changed for theworse.

[0043] In order to preserve the product left for consumption, theconsumer is often forced to use glass or plastic containers or to wrapsaid product left for consumption with aluminium or other plastic filmso as to make sure that it is effectively preserved.

DESCRIPTION OF THE INVENTION

[0044] The present invention aims at overcoming the problems, drawbacksand disadvantages of the prior art by proposing an airtight packagingfor foodstuffs in general, advantageously for cheese, said packagingbeing suitable for being opened with no tearing involved, said packagingfurther being closable more than once, in so doing safeguarding thecorrect preservation and keeping of the product therein contained, saidpackaging further having its longitudinal sealing located along one ofits small faces, this making it possible for an easier reding to be madeof the information relative to the product that is printed on thepackaging itself.

[0045] The above aim has been accomplished thanks to putting intopractice the features described in the main independent claim.

[0046] The dependent claims outline particularly advantageous forms ofembodiment of the present invention.

[0047] A further aim of the present invention is to provide a processfor the production of pouches or packagings for foodstuffs on anindustrial scale and on a continuous basis, said process being viableboth by dint of a flow-pack machine with a horizontal advancement of theproduct to be packed, and of a packaging machine of the vertical type,wherein the product to be packed is unloaded from up above into apackaging that forms beneath the container where the product to bepacked is found, at regular intervals of time.

[0048] Said process is the object of claims from 8 to 12.

[0049] A further object of the present invention is to propose apackaging machine of the “flow-pack” type which is capable of carryingout the sealing operation of a packaging which is formed around aproduct motioned on a small face thereof on the conveyor.

[0050] Said packaging machine is described in claims from 13 to 16.

[0051] The pouch or packaging for the storage of foodstuffs according tothe present invention is manufactured starting from a single film of thepeelable type with a high sealability degree, and advantageously with ahigh impermeability degree, so as to allow said pouch or packaging tohave the necessary airtightness for the keeping of a modifiedatmosphere.

[0052] In such a way, when the two opposite limbs of a given peelablefilm are sealed with each other to yield a packaging according to theinvention, for storage of a given food product, particularly cheese, thepeelability of said film allows the user to open said packaging bydelaminating the sealing, that is detaching the limbs of which above byapplying a traction force to them.

[0053] Thanks to the several advantageous properties of the peelablefilm, the user has therefore access to the product without running anyrisk of tearing the packaging at the time of opening, which is just whathappens to the packagings of the prior art because of the highresistance offered by the materials they are made of, said materials notallowing to be delaminated along any of their sealing lines.

[0054] According to a particular form of embodiment of the presentinvention, the peelable film consists of an oriented polyamide firstlayer which is coupled with a coextruded peelable polyethylene layer,like for example that produced by the German firm Südpäck GmbH,Ochsenhausen.

[0055] According to said form of embodiment, the first orientedpolyamide layer has a thickness of approx. 15 μm, whereas the secondcoextruded peelable polyethylene layer has a thickness of approximately60 μm.

[0056] According to the invention, the sealing between the two portionsof said peelable film to form a packaging is carried out on the innerpolyethylene side.

[0057] At the moment when a certain user applies a traction force on thelimbs in order to open the packaging for the first time, these detachfrom each other at the peelable polyethylene interface.

[0058] According to a first form of embodiment of the present invention,the packaging for foodstuffs, advantageously cheese, obtained with theabove described peelable film, has a first limb which is higher than thesecond limb, therefore said first limb being advantageously suitable forbeing folded over said second limb.

[0059] Said second foldable limb is in fact engaged with the packagingby suitable folding means, an adhesive layer for example, that make itpossible to achieve an effective sealing of the packaging to resort toat the moment when this has already been opened once or more.

[0060] Said closing operation has in fact the undoubted advantage to besuitable for being repeated more than once, making it possible for theuser to help himself with the product contained in said packaging atdifferent moments; in such a way, the user is not forced to resort toother means like other containers or different types of film in order topreserve the product or to fully consume said product, after thepackaging that contains has been opened for the first time, in so doingnot running the risk of having it deteriorating after direct contactwith air and/or losing its own specific taste with time.

[0061] According to a first form of embodiment of the present invention,the process for the production of said packaging involves the employmentof a “flow-pack” type machine with a horizontal advancement of theproduct, equipped with a suitable forming means which is suitable forgetting the packaging ready, said packaging consisting of a peelablefilm suitably unwrapped from a suitable reel, the product to be packedbeing motioned in such a way that one of its small faces lies on theconveyor.

[0062] According to said process, the peelable film is wrapped aroundthe forming means in such a way that a first limb of said film has aheight which is higher than that of a second limb.

[0063] On leaving the forming means the product is therefore wrappedwith the peelable film in an asymmetrical fashion, whereas a suitableseries of rollers is suitable for facilitating the sliding of said filmand further suitable for performing a first vertical sealing, that is asealing that has been executed on the film along its advancementdirection.

[0064] Said first sealing operation is carried out at a slightly lowerlevel than that of the height of said second limb, so that during thefirst packaging opening phase, a given user can avail of the unsealedsurface of said first and second limbs as a valid hand grip for aneasier and faster access to the product.

[0065] According to a particularly advantageous form of embodiment ofthe process according to the present invention, whilst the first sealingphase inside the packaging that is acquiring its shape is taking place,a gas or a suitable mixture of gases is pumped in so as to create amodified atmosphere.

[0066] After that, once it has been longitudinally sealed and at thatstage already containing the product to be packed, the film gets to acouple of sealing plates which are suitable for carrying out a secondsealing in the transversal direction which is itself suitable foryielding the first short side of the packaging.

[0067] According to a feature of the present invention, the sealingplates are fixed to a mechanism that sets and keeps them in motion,which operates motioning the plates so as to make them follow a rotarymotion around perpendicular axes.

[0068] The speed of rotation is in coordination with the advancementspeed of the products on the conveyor and it accounts for the length ofeach unit of product so as to act exactly in correspondence with theends thereof.

[0069] Furthermore, simultaneosly with the sealing operation, the filmis cut by a blade which the sealing plates are equipped with, or,according to a further form of embodiment, by a mechanism which isseparate therefrom.

[0070] Once that second sealing has been accomplished, as the productadvances, the sealing plates of which above are rotated, and theyapproach the limbs of the peelable film again, downstream from theproduct, where the third sealing is carried out, which is also of thetransversal type and which completes the packaging yielding to thesecond short side of it.

[0071] According to a form of embodiment of the present invention, eachof the sealing plates is made so as to be integral with cylinders thatrotate at an angular speed that is synchronised with the speed withwhich the product advances on the conveyor, so as to complete a rotationaround its own axis for each unit of product that passes by.

[0072] As it was explained above, each sealing plate is provided with ablade which is suitable for cutting the film made of plastic material,said blade being positioned at equal distances from the edges of thesealing plate, and being integral to it.

[0073] At the end of the third sealing, the peelable film is suitablycut as described above and the first limb, that is the longer limb, isfolded over onto the packaging; at that stage a suitable equipmentapplies an adhesive label onto said first limb so as to allow itscoupling to the packaging which is then ready for packaging and storing.

[0074] As said, equipping the packaging with an adhesive label makes itpossible for said packaging to be advantageously closed and opened againand again, safeguarding a perfect storage of the product with time, oncethe packaging has been opened, that is once the delamination of itsfirst longitudinal sealing has taken place, thing that leaves thepackaging perfectly sealed on the three remaining sides.

[0075] According to a further form of embodiment, the packagingaccording to the present invention is provided with a zip mechanicalclosing system, which is itself also made of a plastic material, saidclosing system being of an already known type and generally employed inthe packaging field at large.

[0076] According to an advantageous form of embodiment of the invention,said zip is located outside of the first longitudinal sealing and notwithin the sealed area containing the product, as it happens for somepackagings known in the art.

[0077] The positioning of the zip outside of said first sealing resultsto be extremely advantageous because of the fact that it is located inan area of the packaging which is not involved in containing the productand the modified atmosphere that surrounds it.

[0078] This means in other words that while sealing the zip to the filmthere is no risk whatsoever to cause little accidental openings thatwould inevitably jeopardise the airtightness of the packaging itself andthe keeping of the product therein contained.

[0079] According to a further form of embodiment of the presentinvention, the process for the production of the zip equipped pouches orpackagings involves the employment of a forming means constituted by atubular plate that the wraps the peelable film around the product topack in a symmetrical manner, that is without leaving a first limb whichis more protruding than the other, as described in the case representedby the first form of embodiment mentioned above.

[0080] On leaving said forming means, the peelable film wraps theproduct and a plurality of rollers make the film itself advance andfurther carry out the first longitudinal sealing of to in a way which isanalogous with that of the process which has just been described above.

[0081] During the first longitudinal sealing operation, a gas or amixture thereof is blown into the film, said gas or mixture thereofbeing suitable for creating the desired modified atmosphere and,furthermore, the zip is positioned in the area of the packaging thatresults to be above said longitudinal sealing.

[0082] Said zip can be positioned by respectively sealing the two maleand female elements that it consists of with both the two limbs of thefilm, or sealing the support element to which the zip can beadvantageously coupled onto them.

[0083] At the end of said operation, the packaging keeps advancingtowards a couple of sealing plates (that can be of the rotational type,as detailed above), which are brought closer to the packaging in orderto carry out said sealings of the second and third transversal types soas to close the two short sides of the packaging and to obtain acomplete airtightness of said packaging.

[0084] At the same time, the film is transversally cut, and thepackaging which is obtained by it results to be ready for the followingpackaging and storage phases.

[0085] It should be emphasised that even said further form of embodimentof the present invention allows the achievement of an airtight packagingwhich has the advantage of being capable of being repeatedly opened andclosed without risking tearing the packaging itself and withoutjeopardising the correct storage of the food product therein contained,once the packaging has been opened for the first time by carrying outthe delamination of the longitudinal sealing of the original packaging.

[0086] Such an advantage results to be particulmarly useful mostly incase the packaging is around blocks of cheese, which can then beconsumed several times, even several days one from the other, withoutrunning the risk of having to dispose of portions of cheese that haveundergone degradation on account of their prolonged exposure to air.

ILLUSTRATION OF DRAWINGS

[0087] Other features and advantages of the present invention willresult to be more easily understandable after reading the followingdescription, that is only given by way of a not limiting example, withreference to the figures shown in the tables hereto attached, in which:

[0088]FIG. 1 shows a schematic side and partially a cutaway view of apackaging according to the present invention;

[0089]FIG. 2 shows a plan view from above of what shown in FIG. 1; and

[0090]FIG. 3 shows a plan view from above of a packaging according to afurther form of embodiment of the present invention;

[0091]FIG. 4 shows a schematical view of a pakaging machine of the“flow-pack” type provided with a device enabling a product placed on itssmall face on a conveyor to be provided with a packaging according tothe invention.

DESCRIPTION OF A FORM OF EMBODIMENT OF THE INVENTION

[0092] In the figures, reference signs 10, 20 generally indicate a pouchor packaging made of peelable film according to the present invention.

[0093] In FIGS. 1 and 2 a first form of embodiment is shown of thefoldable packaging 10 according to the present invention.

[0094] According to said form of embodiment, a packaging 10 made of apeelable film 11 consisting of an oriented polyamide first layer whichis coupled with a coextruded peelable polyethylene layer can be producedby wrapping said film 11 around a certain product 12 passing through asuitable tubular forming means (not shown in the figure), said wrappingbeing carried out so as to obtain a first limb 11′ and a second limb 11″having different heights.

[0095] In so doing, the first limb 11′ which is higher than the secondlimb 11″, is suitably folded over said second limb, achieving packaging10 according to the present invention.

[0096] It has to be noted that the sealing 13 operation is carried outon the same inner polyethylene layer of the film, whereby sealing 13 isperfectly homogeneous and airtightness can be guaranteed.

[0097] Moreover, once the sealing 13 operation of said limbs 11′, 11″along the product advancement direction, said direction beingperpendicular to the plane on which the sheet of FIG. 1 lies, sealings14, 15 are carried out in succession (shown on FIG. 2) as well as thenecessary film cutting operations that follow when the packaging hasbeen fully completed according to the invention.

[0098] In this context it can be noted that side sealing operations 14,15 are also carried out by coupling the inner polyethylene portions offilm 11.

[0099] Furthermore, it may be noted in both FIGS. 2 and 3, the sealingoperation is always carried out on a film which has been folded onlyonce, i.e. the sealing blocks or rolls have need to link together onlytwo layers of the film.

[0100] This fact gives the film a great reliability in terms ofairtightness, contrary to several solutions known in the art, accordingto which the packagings are formed by welding three or four film layerssuperimposed to each other, thereby running a considerable risk ofcreating air passages or, in any case, weakening the airtightness of thepackaging.

[0101] Finally, a suitable coupling means 16 like an adhesive label isapplied to the first longer limb 11′ through which said first foldablelimb 11′ is engaged to packaging 10 (arrow A in FIG. 1) making itpossible to close and open said packaging even when it has been openedfor the first time, with an ensuing delamination of sealing 13, whichmakes packed product 12 accessible.

[0102]FIG. 2 shows how the first sealing 13 is accomplished at aslightly lower level than the height of the second limb 11″ in such away that during the opening phase, the user can employ the unsealedsurfaces 11′, 11″ as hand grip surfaces, for an easier and quickeropening operation of packaging 10.

[0103]FIG. 3 shows another form of embodiment 20 of the packagingaccording to the present invention.

[0104] Said packaging 20 results to be provided with a mechanicalzipping closing system 21 made of plastic material.

[0105] According to that form of embodiment, packaging 20 is obtained bywrapping film 11 around the product 12 with a symmetrical fashion, and,once said first sealing 13 has been carried out, zip 21 is applied topackaging 20 by welding it to the film.

[0106] After that, the film is further sealed 14, 15 and cut to obtain apackaging that can be opened and closed whenever wanted, all the sameaccomplishing a correct and effective preservation of the producttherein contained.

[0107]FIG. 4 shows a schematical view of a packaging machine of the“flow-pack” type.

[0108] A single film is here unwrapped from a reel 50 and fed to atubular forming device through which a series of products 12 lying on aconveyor with their small faces are made to advance.

[0109] A pair of rollers 55, 56 carry out a first longitudinal sealing13 of the film limbs, while a device 60 provided a pair of weldingblocks and cutting blades carries out the sealing and cutting operationsof the transversal edges 14, 15 of the packaging.

[0110] The invention has been so far described with reference to someparticular preferred forms of embodiment thereof.

[0111] It is however to be given for granted that the present inventionis not limited by these forms of embodiment, but that it covers all themodifications and variations that can be taken in consideration withoutstepping out of the scope of the present invention as it is defined bythe claims.

[0112] It is therefore obvious that the the invention can be put inpractice, for example by dint of an intermittent advancement machine,continuously operating like the one described above.

[0113] In fact there is found to be provided a particularly advantageousform of embodiment of the present invention according to which saidre-closable packaging is produced by means of a packaging machine of thevertical type, wherein the tubular forming means is located so as to bevertical, and the product is gravitationally unloaded into said tubularforming means and, then, into the packaging that forms therebelow.

[0114] The technical measures to take in order to get to have the sameadvantages described above with reference to a packaging-machine of the“flow-pack” type can be directly inferred from the previous descriptionof said packaging machine.

1. An airtight pouch or packaging (10, 20) made of synthetic materialfor the preservation of food products (12), said packaging beingobtained by sealing (13, 14, 15) and cutting said synthetic material byan automatic packaging machine with a horizontal or vertical motioningof the product, said packaging (10, 20) being constituted by a singlepeelable type film (11) consisting of an oriented polyamide layercoupled with a coextruded peelable polyethylene layer, said film beingfolded once on the polyethylene layer side in order to form the innerpart of said packaging.
 2. A packaging (10, 20) according to claim 1 ,wherein said packaging is provided with coupling and closing means (16,21), that make it possible to repeatedly open and close said packaging(10, 20) after this has been used for the first time, said coupling andclosing means not involving the sealing area of said packaging.
 3. Apackaging (10, 20) according to claim 2 , wherein said orientedpolyamide layer has a thickness of approximately 15 μm, and by the factthat said coextruded peelable polyethylene layer has a thickness ofapproximately 60 μm.
 4. A packaging (10) according to claim 1 , whereinsaid peelable film has a first limb (11′) and a second limb (11″), saidfirst limb (11) and second limb (11″) having different heights so thatsaid first limb (11′) has a greater height than that of said second limb(11″) and it can be folded over (A) the packaging in order to accomplishthe closing (10) thereof.
 5. A packaging (10) according claim 4 ,wherein said coupling and closing means (16) are made of an adhesivelabel.
 6. A packaging (20) according to claim 1 , wherein, said couplingand closing means (21) consist of a zipping closing system.
 7. Apackaging (10, 20) according to claim 1 , comprising a couple ofportions suitable for being hand gripped in order to obtain thedelamination of a sealing and the consequent opening of the packaging.8. A process for the production of an airtight packaging (10) suitablefor the preservation of products (12), by means of a “flow-pack” typeautomatic packaging machine, in which a series of products iscontinuously advanced on a horizontal conveyor towards a packagingstation comprising a tubular forming device through which said products(12) are made to advance, said process comprising the followingoperational steps: unwrapping of a single synthetic material film from areel; wrapping of the film around said tubular forming device withinwhich a product (12); carrying out a first longitudinal sealing (13) ofthe limbs (11′, 11″) of said film; carrying out a second (14) and athird (15) transversal sealings on the film edges in order to airtightlyseal said packaging, cutting said film in order to release the packagedproduct (12), wherein said film (11) is of the peelable type consistingof an oriented polyamide layer coupled with a coextruded peelablepolyethylene layer, said film being wrapped around the product on thepolyethylene layer side in order to form the inner part of saidpackaging, whereby said said longitudinal and transversal sealings areobtained by, respectively, welding together said limbs (11′, 11″) andsaid film edges on their polyethylene layer side.
 9. A process accordingto claims 8, whereby a modified atmosphere inside the packaging isformed by the blowing of a gas or of a predetermined mixture thereofinto the packaging itself.
 10. A process according to claim 8 , whereinthe film is wrapped around said tubular forming device in such a waythat one (11′) of said limbs (11′, 11″) has a height which is differentfrom the height of the other (11″) of said limbs, and in that once, saidtransversal sealings have been carried out, the longer limb (11′) isfolded over the other limb (12), and kept in position by an adhesivelabel (16) for example.
 11. A process according to claim 8 , wherein azipping closing system is welded to said limbs (11′, 11″), outside ofthe sealing area, in order to allow said packaging to be opened andreclosed after the first opening operation.
 12. A process for theproduction of an airtight packaging (10) suitable for the preservationof products (12), by means of an automatic packaging machine of thevertical type with gravitational falling of the product inside of atubular forming device around of which a synthetic film is wrapped inorder to form said packaging, said process comprising the followingoperational steps: unwrapping of a synthetic material film from a reel;wrapping of the film around a said tubular forming device within which aproduct (12) is made to fall at predetermined time intervals; carryingout a first longitudinal sealing (13) of the limbs (11′, 11″) of saidfilm; carrying out a second (14) and a third (15) transversal sealingson the film edges in order to airtightly seal said packaging, cuttingsaid film in order to release the packaged product (12), wherein saidfilm (11) is of the peelable type consisting of an oriented polyamidelayer coupled with a coextruded peelable polyethylene layer, said filmbeing wrapped around the product on the polyethylene layer side in orderto form the inner part of said packaging, whereby said said longitudinaland transversal sealings are obtained by, respectively, welding togethersaid limbs (11′, 11″) and said film edges on their polyethylene layerside.
 9. A process according to claims 12, wherbey a modified atmosphereinside the packaging is formed by the blowing of a gas or of apredetermened mixture thereof into the packaging itself.
 10. A processaccording to claim 12 , wherein the film is wrapped around said tubularforming device in such a way that one (11′) of said limbs (11′, 11″) hasa height which is different from the height of the other (11″) of saidlimbs, and in that once, said transversal sealings have been carriedout, the longer limb (11′) is folded over the other limb (12), and keptin position by an adhesive label (16) for example.
 11. A processaccording to claim 12 , wherein a zipping closing system is welded tosaid limbs (11′, 11″), outside of the sealing area, in order to allowsaid pakcaging to be opened and reclosed after the first openingoperation.
 12. Packaging machine of the “flow-pack” type with theproduct advancing on a continuous basis or intermittently, on ahorizontal conveyor, said machine being provided with a tubular formingdevice through which said product is made to advance and around which asynthetic film is wrapped in order to form a packaging around saidproduct, said product lying on one of its small faces on said horizontalconveyor, comprising a couple of sealing plates which are suitable forcarrying out the sealing operation of the edges of the packaging thatare perpendicular to the plane on which the product lies, said sealingplates being rotatable, in a coordinated and synchronised manner withrespect to the advancement motion of the product on said conveyor,around their respective axes that are perpendicular to the plane onwhich the product lies, so as to be placed one in front of the other incorrespondence with their respective front and and back edges of thepackaging to be sealed and that contains the product.
 13. Packagingmachine according to claim 13 , wherein said sealing plates compriserespective cutting blades, which exert their mutual action as they arelocated one opposite to the other and are suitable for cutting the filmthat makes up the packaging in correspondence with the sealing that hasbeen carried out.
 14. Packaging machine according to claim 17 ,characterised in that said cutting blades are at equal distances fromthe edges of the respective sealing blades.
 15. Packaging machineaccording to claims 16, characterised in that the sealing plates rotateat such an angular speed that they complete one rotation for each unitof product motioned on the conveyor.